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Health & Fitness · Medical

eGFR Calculator — Kidney Function (CKD-EPI 2021)

Estimate kidney function (eGFR) from a blood creatinine result, age and sex using the 2021 CKD-EPI creatinine equation recommended by the US National Kidney Foundation, which doesn't use race. Enter creatinine in mg/dL or µmol/L and see the KDIGO GFR category from G1 to G5.

Your inputs

Quick start — try a typical case

mg/dl
years

Your result Live

eGFR

92 mL/min/1.73 m²

Stage G1 — normal or high

Creatinine Used
1.00 mg/dL (88 µmol/L)
What the Stage Means
On its own this is not kidney disease — CKD at G1–G2 needs other signs of kidney damage, such as protein in the urine.

GFR categories (KDIGO)

6 rows
StageeGFRDescription
G1≥ 90Normal or high
G260–89Mildly decreased
G3a45–59Mildly to moderately decreased
G3b30–44Moderately to severely decreased
G415–29Severely decreased
G5< 15Kidney failure

eGFR is an estimate; muscle mass, diet, pregnancy and some medicines affect creatinine. Results need a clinician's interpretation, usually alongside a urine albumin test.

Population-average estimates for healthy adults, not medical advice. Talk to a doctor or registered dietitian before major changes to diet or exercise, or if you are pregnant or have a health condition.

How this is calculated

eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 (if female)

κ
0.7 for women, 0.9 for men
α
−0.241 for women, −0.302 for men
Scr
Serum creatinine in mg/dL (µmol/L ÷ 88.4)

Kidneys filter creatinine, a waste product from muscle, out of the blood, so a higher blood creatinine usually means slower filtering. The CKD-EPI 2021 equation turns creatinine, age and sex into an estimated filtration rate per standard body size (1.73 m²). It replaced the 2009 version, which included race.

Assumptions & sources

  • Adults 18 and over, with a standardised (IDMS-traceable) creatinine test and stable kidney function.
  1. 1CKD-EPI Creatinine Equation (2021) — National Kidney Foundation
  2. 2eGFR equations for adults — National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Calculator ID HLTH-EGFR-001 · version 1.0.0

Common questions

What is a normal eGFR?

90 or above is normal; it naturally drifts down with age. Below 60 for three months or more suggests chronic kidney disease.

Why doesn't this ask for race?

The 2021 CKD-EPI equation was refitted without race, and kidney organisations now recommend it over the 2009 version.

My creatinine is in µmol/L — what do I do?

Choose µmol/L; the calculator divides by 88.4 to convert to mg/dL.